I used hand held tools when I made this one but there are certainly better tools for most of the work here. However this isn't a how-to on what tools to use or how to use them, it's all about the toy. I'll leave it up to you to make sure whatever tools you choose, you use them safely and effectively.
Anyway, enough talkin', let's get on to the buildin'.
Drill & 1/8" bit
1 3/4" flat bottom "wall rail" (3 feet)
3/8" quarter-round molding (2 feet)
2 1/4" wood ball knob (1)
1 1/2" wood ball knob (1)
1 1/2" wood toy wheels (12)
1 1/4" wood axle pegs (12)
3/8" wood round beads (about 20)
1/16" round elastic cord (3-4 feet)
3/8" bungee cord or similar sized rope (2 feet)
3/8" screw eye (1)
1/2"-3/4" fun colored, two hole button (1)
Step 1: Cutting All the Pieces
I then cut the quarter-round into six 2" sections to be used as mounting points for the centipede's legs.. err, wheels. I'll refer to these as the "axle casings" from here on out. You could also use half-round for these parts, I just used what I had sitting around in the garage from some previous projects.
Step 2: Sanding and Drilling
The next part was the drilling. Not having a drill press makes getting the holes through the wall rail straight fairly difficult. I should also mention that having a 1/8" drill bit that's longer than three inches comes in real handy here. I managed, using a woodworking vise and the level on the back-end of my hand held drill, to get the holes drilled satisfactorily.
As you can see in the photo, drill two holes completely through each section of wall rail (end to end) for the elastic cord to run through. Having two holes gives us a little more vertical rigidity and keeps the body sections from rotating freely around the elastic cord.
Drilling the axle casings with the hand held drill was somewhat easier since they're only two inches long. The holes in the axle casings should also be drilled completely through.
Step 3: Quick Test Fitting & Gluing the Axle Parts
These photos also show a little closer look at the chamfer I put on the edges. If you want to spend a little more time on them you could round them off to match the rounded wheels and give it an overall smoother look. This might certainly be more desirable if you're planning to finish the wood with only clear lacquer. I knew we were going to paint ours and I kinda wanted it to be a little more "chunky" looking.
This is also the time to glue the axle casings to the bottom (flat side) of the wall rail sections. Glue one axle casing to each section placing it in the center. I also clamped them and let the glue dry overnight.
Step 4: Paint and Lacquer
Once the paint was dry we applied 4 or 5 coats of clear lacquer over a couple days with some very light sanding between coats. This gives the whole thing a wonderful glossy shine in addition to protecting the paint.
A handy tip to help with applying the clear lacquer is to use a piece of thin steel rod (or a wire coat hanger if you can find one!) to lace through the sections (with one of the 3/8" beads between each one). It makes it easy to get all the sides covered quickly and evenly. I also clamped the wire rod to a 2x4 in the garage ceiling to let it hang dry.
NOTE: You can either screw the eye screw into the 2 1/4" wood ball knob that will become the head before or after painting/finishing. I added it before then just taped over it to keep the paint and lacquer off. The eye screw should be inserted about 3/4" away from the center hold on the rounded side of the ball knob. And if you're painting a face on the ball knob, make sure that the eye screw sits in the "forehead" area of the finished product.
Step 5: Stringing It All Together
Once you've fed the cord through the top holes in all the body sections, it's time to attach the head. The ball knob I used for the head had a small cavity inside so the cord was tough to feed straight through. This is where the paper clip comes in handy. Straighten the paper clip then bend a very small "hook" into one end. Feed the elastic cord into the hole on the back of the head piece. Then using the hook on the paper clip, grab the elastic cord and pull it through the front hole.
Once through, feed it through the button "nose" as shown in the photos and then back through the head. Once you're done with the head piece, feed the elastic cord back through all the body pieces but this time using the lower hole through each body section. And don't forget to add a bead between each section on this pass as well.
Once the elastic cord is laced through all the pieces/sections and you have the ends poking out the "tail" piece, tie them off so they don't get sucked back out. We'll finish them up in a minute.
At this stage I went ahead and added all the wheels and axle pegs in. You might want to do a test fitting like I did as all axle pegs are not equal and you may find that some fit better than others in the different sections. Once you're happy with the test fitting, put a small dab of glue either on each axle peg (after putting it through a wheel) or in the hole in the axle casing then insert the axle peg and wheel assembly into the axle casing with a slight twist to spread the glue around. Be careful to leave the axle peg out enough to allow the wheel to spin freely.
You'll probably want to let the glue on the axles dry for an hour or so before finishing things up in the next step.
Step 6: Finishing It Up
Now I hadn't really planned to do a fancy tail on mine. If you wanted to get fancy you could make a "tail" from another piece of the wall rail and taper it off. I opted to lace 5 additional beads onto each three inches of extra elastic cord I left to keep it simple.
Once you're happy with the tail, it's time to add the pull string. Grab the 3/8" bungee cord (or rope) and tie a knot in one end. Thread the other end through the hole in the 1 1/2" wood ball knob then tie another knot to keep the ball knob held in place. Then simply thread the other end through the screw eye in the head piece and tie another knot to keep it in place.
As with anything for kids, make sure you're careful to assemble all the pieces well and keep an eye on things as they play. Kids can be rough on toys and there are quite a few small parts that could break off and the elastic cords can also be hazardous for young children.
I've include some additional photos of our finished centipede below as well as a happy Lucy playing with it. Enjoy!